Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 7 - Colorado River Basin Region

Water Body Name:	Colorado River (Imperial Reservoir to California-Mexico Border)
Water Body ID:	CAR7270000020050815175128
Water Body Type:	River & Stream


DECISION ID	69080	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Selenium
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Reason for Delisting:	Applicable WQS attained; due to change in WQS
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.5 of the Listing Policy. Under section 3.1 and 3.5, a single line(s) of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. (LOE 2968) Three of the five samples exceed the OEHHA Screening Value for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528) (LOE 46528) Zero of the five samples exceed the OEHHA Fish Contaminant Goal for the "Commercial or Recreational Collection of Fish, Shellfish, or Organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528) (LOE 126028) Zero of the six samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed, in water, under section 3.1. (LOE 126092) Zero of the six samples exceed the California Toxics Rule Criterion Continuous Concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed, in water, under section 3.1. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3.Four lines of evidence are available in the administrative record to assess this pollutant. (LOE 2968) Three of the five samples exceed the OEHHA Screening Value for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed, in tissue, under section 3.5. (Note: LOE 2968 was replaced by LOE 46528) (LOE 46528) Zero of the five samples exceed the OEHHA Fish Contaminant Goal for the "Commercial or Recreational Collection of Fish, Shellfish, or Organisms" beneficial use assessed, in tissue, under section 3.5. (LOE 2968 was replaced by LOE 46528, which was assessed based on the new guideline.) (LOE 126028) Zero of the six samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed, in water, under section 3.1. (LOE 126092) Zero of the six samples exceed the California Toxics Rule Criterion Continuous Concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed, in water, under section 3.1. The sample sizes (with the replacement of LOE 2968 by LOE 46528) are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 69080, Selenium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

2968

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Three out of 5 samples exceeded (TSMP, 2002). A total of 5 filet samples of largemouth bass were collected. Bass were collected in 1992, 1999, and 2001-02. Bass exceeded the guideline in 1999 and 2001-02.

Data Reference:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Colorado River Basin RWQCB Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Placeholder reference 2006 303(d)

Evaluation Guideline:

OEHHA Screening Value 2 ug/g.

Guideline Reference:

Placeholder reference 2006 303(d)

Spatial Representation:

Two stations were sampled: about 2 miles downstream of the Needles Marina Resort and from Squaw Lake boat launch ramp to 1/4 mile north of Senator Lake.

Temporal Representation:

Samples were collected annually in 1992, 1999 and 2001-02.

Environmental Conditions:

QAPP Information:

Toxic Substances Monitoring Program 1992-93 Data Report.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 1996-2000. Department of Fish and Game.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002. Department of Fish and Game.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 69080, Selenium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

46528

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

None of 5 samples exceeded (TSMP, 2002). A total of five filet samples of largemouth bass were collected. Bass were collected in 1992, 1999, and 2001-02. Bass exceeded the guidelines in 1999 and 2001-02.

Data Reference:

Toxic Substances Monitoring Program data for years 1992-2002 and Coastal Fish Contamination Program for years 1 and 2. State Water Resources Control Board

Toxic Substances Monitoring Program 1991 Data Report. 93-1WQ. State Water Resources Control Board (SWRCB), Division of Water Quality. Sacramento, CA.

SWAMP Data:

Water Quality Objective/Criterion:

Colorado River Basin RWQCB Basin Plan: No individual chemical or combinationof chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006

Evaluation Guideline:

OEHHA Fish Contaminant Goals(FCGs) 7.4 mg/kg

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Two stations were sampled: about 2 miles downstream of the Needles Marina Resort and from Squaw Lake boat launch ramp to 1/4 mile notrh of Senator Lake.

Temporal Representation:

Samples were collected annuallly in 1992, 1999 and 2001-02.

Environmental Conditions:

QAPP Information:

Toxic Sustances Monitoring Program 1992-1993 Data Report.

Environmental Chemistry Qaulity Assurance and Data Report for the Toxic Substances Monitoring Program, 1996=2000. Department of Fish and Game.

Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002. Department of Fish and Game.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 69080, Selenium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126028

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality standard for Selenium.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Maximum Contaminant Level for selenium in the Basin Plan is 0.05 mg/L (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 69080, Selenium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126092

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101815	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Antimony
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of five samples exceed the California Maximum Contaminant Level for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Maximum Contaminant Level for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of five samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "total" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed. Zero of six samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "dissolved" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of five samples exceed the California Maximum Contaminant Level for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Maximum Contaminant Level for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of five samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "total" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed. Zero of six samples exceed the California Toxics Rule criteria for the protection of human health from consumption of organisms for the "dissolved" fraction for the "Commercial or recreational collection of fish, shellfish, or organisms" beneficial use assessed. These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101815, Antimony	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126084

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Antimony criteria for the protection of human health from consumption of organisms only is 4300 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101815, Antimony	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126116

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Antimony.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Antimony criteria for the protection of human health from consumption of organisms only is 4300 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101815, Antimony	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125945

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for antimony is 0.006 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101815, Antimony	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126050

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for antimony is 0.006 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101816	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Arsenic
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of six samples exceed the California Maximum Contaminant Level for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Maximum Contaminant Level for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "total" fraction, for the " Warm Freshwater Habitat " beneficial use assessed. Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "dissolved" fraction, for the " Warm Freshwater Habitat " beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of six samples exceed the California Maximum Contaminant Level for the "total" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Maximum Contaminant Level for the "dissolved" fraction for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "total" fraction, for the " Warm Freshwater Habitat " beneficial use assessed. Zero of six samples exceed the California Toxics Rule criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater, for the "dissolved" fraction, for the " Warm Freshwater Habitat " beneficial use assessed.. These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101816, Arsenic	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126088

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101816, Arsenic	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125978

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101816, Arsenic	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126070

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101816, Arsenic	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126110

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101817	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Barium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of ____samples is needed to determine if a beneficial use is fully supported using table _____. 4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101817, Barium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126005

Pollutant:

Barium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for barium is 1 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101818	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Beryllium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101818, Beryllium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126046

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Beryllium.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for beryllium is 0.004 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2014-08-27

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101819	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Boron
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of six samples exceed the Division of Drinking Water Notification Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985) protective of various agricultural uses of water (including irrigation of various types of crops and stock watering), for the "Agricultural Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of six samples exceed the Division of Drinking Water Notification Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985) protective of various agricultural uses of water (including irrigation of various types of crops and stock watering), for the "Agricultural Supply" beneficial use assessed. The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101819, Boron	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126097

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Drinking water notification levels are published by the Division of Drinking Water. Notification levels are for chemicals for which there is no drinking water MCL. If a notification level is exceeded, local government notification is required and customer notification is recommended. The notification level for Boron is 1 mg/L.

Guideline Reference:

Drinking Water Notification and Response Levels: An Overview

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101819, Boron	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125966

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. The guideline for boron is 700 ug/L (0.7 mg/L).

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101820	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Cadmium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the Two samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the Two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the Two samples exceed the Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the Two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101820, Cadmium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126131

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2015-02-12 and 2015-05-21

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101820, Cadmium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125942

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Maximum Contaminant Level for cadmium in the Basin Plan is 0.005 mg/L (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2015-02-12 and 2015-05-21

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101821	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Chloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2, a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the six samples exceed the Drinking Water Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six samples exceed the USEPA National Recommended Water Quality Criteria, criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six samples exceed the Drinking Water Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six samples exceed the USEPA National Recommended Water Quality Criteria, criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101821, Chloride	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126002

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101821, Chloride	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126003

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used: 500 mg/l Chloride (CCR, title 22).

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101823	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Fluoride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the six samples exceed the California Primary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985, which contains criteria protective of various agricultural uses of water) for the "Agricultural Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six samples exceed the California Primary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six samples exceed the Water Quality for Agriculture criteria (published by the Food and Agriculture Organization of the United Nations in 1985, which contains criteria protective of various agricultural uses of water) for the "Agricultural Supply" beneficial use assessed. The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101823, Fluoride	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125968

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. A 1 mg/L criteria is the recommended maximum concentration of Fluoride in irrigation water.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101823, Fluoride	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126136

Pollutant:

Fluoride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The California Primary Maximum Contaminant Level (MCL) for Fluoride, is 2 mg/l.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101810	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Indicator Bacteria
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the six sample(s) exceed the Statistical Threshold Value for the " Water Contact Recreation" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six sample(s) exceed the Statistical Threshold Value for the " Water Contact Recreation" beneficial use assessed. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101810, Indicator Bacteria	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126138

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and the results are as follows: 0 of the 6 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): USGS-09521100

Temporal Representation:

The samples were collected between the days of 2014-08-27 and 2016-12-20 .

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101824	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Lead
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence are necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the six sample(s) exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the one sample(s) exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six sample(s) exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the six sample(s) exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the one sample(s) exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the six sample(s) exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101824, Lead	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126076

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Maximum Contaminant Level for lead in the Basin Plan is 0.015 mg/L (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101824, Lead	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126094

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Maximum Contaminant Level for lead in the Basin Plan is 0.015 mg/L (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2015-05-21 and 2015-05-21

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101824, Lead	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125970

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101827	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the 16 samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 16 samples exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101827, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126784

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 16 samples exceeded the water quality standard for Nitrate + Nitrite as N.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for nitrate + nitrite (as N) is 10.0 mg/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) (QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)

Temporal Representation:

The samples were collected between the dates of 2010-12-02 and 2012-06-14

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101828	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Nitrogen, Nitrate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the nine sample(s) exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One line of evidence is available in the administrative record to assess this pollutant. Zero of the nine sample(s) exceed the California Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed.. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101828, Nitrogen, Nitrate	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126700

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality standard for Nitrate as N.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Nitrate as N is 10000 ug/L (Title 22 of the California Code of Regulations).

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 4 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35)

Temporal Representation:

The samples were collected between the dates of 2010-12-17 and 2011-09-21

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101782	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence are available in the administrative record to assess this pollutant. Four of the 186 samples exceed the Water Quality Control Plan, Colorado River Basin, Warm Water Habitat Objective for the "Warm Freshwater Habitat" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. [Four of the 186 samples exceed the Water Quality Control Plan, Colorado River Basin, Warm Water Habitat Objective for the "Warm Freshwater Habitat" beneficial use assessed. This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101782, Oxygen, Dissolved	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126762

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

186

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 4 of 186 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Colorado River Basin, WARM Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 5.0 mg/l at any time.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 7 monitoring site(s) (COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	131318	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Sodium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This decision was updated by Regional Board staff with assessment of data using the flow-weighted site-specific salinity objective for the Colorado River. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Lines of Evidence (LOEs) 126075 and 125984 were replaced with LOE 198742, in which flow-weighted data was assessed with the flow-weighted objective in the Basin Plan. One line of evidence is available in the administrative record to assess this pollutant. Zero (0) of the thirty-nine (39) samples exceeded the water quality objective(s). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero (0) of the thirty-nine (39) samples exceed the site specific water quality objective(s) in Basin Plan. This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 131318, Sodium	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

198742

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data associated with the Quality Of Water Colorado River Basin Progress Report No. 25 (U.S. Department of the Interior, Bureau of Reclamation, Upper Colorado Region, 2017), to determine beneficial use support and results are as follows: 0 of 39 samples exceeded the water quality standard.

Data Reference:

Quality Of Water Colorado River Basin Progress Report No. 25

Data Associated with Quality Of Water Colorado River Basin Progress Report No. 25

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Because Sodium is a component of TDS, and since the Colorado River and associated lakes have site specific water quality objectives for salinity expressed as TDS, it is more appropriate to treat the Sodium assessment for the Colorado River similar to the assessment for TDS in making any listing decisions.

Colorado River Basin Region Water Quality Control Plan includes the following Salinity/TDS objectives for the Colorado River above and below Imperial Dam: Colorado River (Above Imperial Dam) - The Seven States Colorado River Salinity Control Forum developed water quality standards in 1975 for salinity. The flow-weighted average annual numeric criteria for salinity (total dissolved solids) were established at three locations on the lower Colorado River: 1) Below Hoover Dam AZ-NV, 723 mg/l; 2) Below Parker Dam AZ-CA, 747 mg/l; 3) Imperial Dam AZ-CA, 879 mg/l. (CRBRWQCB, 1/18/2019)

Colorado River (Below Imperial Dam) – Below Imperial Dam, the River's salinity will be controlled to meet the terms of the agreement with Mexico on salinity in Minute No. 242 of the International Boundary and Water Commission, entitled "Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River". This agreement states that measures will be taken to assure that the waters delivered to Mexico upstream from Morelos Dam will have annual average salinity concentration of no more than 115 ppm (+ 30 ppm) total dissolved solids greater than the annual average salinity
concentration of Colorado River water arriving at Imperial Dam. Title I of
Public Law 93-320 is the legislation which implements the provisions of Minute No. 242. Minute No. 242 and Title I constitute a federal numeric criterion and plan of implementation for the River below Imperial Dam. (CRBRWQCB, 1/18/2019)

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Objective/Criterion Reference:

Response to Comments, Clean Water Act Sections 305(b) and 303(d) 2018 Draft Integrated Report for the Colorado River Basin Region, CRBRWQCB, November 2019)

Objective/Criterion Reference:

Minute 242: Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River

Objective/Criterion Reference:

Water Quality Standards for Salinity Including Numeric Criteria and Plan of Implementation for Salinity Control Colorado River System.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 3 monitoring site(s) 09427520 Colorado River below Parker Dam, AZ-CA, 09429490 Colorado River above Imperial Dam, AZ-CA, 09421500 Colorado River below Hoover Dam, AZ-NV (Out of state, upgradient, data used reviewed)

Temporal Representation:

The samples were collected between the dates of 1975 and 2013.

Environmental Conditions:

QAPP Information:

USGS/Bureau of Reclamation Data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	131319	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Specific Conductivity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This decision was updated by Regional Board staff with assessment of data using the flow-weighted site-specific salinity objective for the Colorado River. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Line of Evidence (LOE) 126840 was replaced with LOE 198741 because it contains flow-weighted data and the flow-weighted objective from the Basin Plan. One line of evidence is available in the administrative record to assess this pollutant. Zero (0) of the thirty-nine (39) samples exceeded the water quality objective(s). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero (0) of the thirty-nine (39) samples exceed the site specific water quality objective(s) in Basin Plan. This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 131319, Specific Conductivity	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

198741

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Quality Of Water Colorado River Basin Progress Report No. 25

Data Associated with Quality Of Water Colorado River Basin Progress Report No. 25

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Specific Conductivity = TDS/r; where r ranges from 0.55 to 0.75 (Water-Resources Investigations Report 86-4124, USGS, 1987 and Hem. 1970). Corresponding TDS and Specific Conductivity values are as follows:
Colorado River Basin Region Water Quality Control Plan includes the following Salinity/TDS objectives for the Colorado River above and below Imperial Dam: Colorado River (Above Imperial Dam) - The Seven States Colorado River Salinity Control Forum developed water quality standards in 1975 for salinity. The flow-weighted average annual numeric criteria for salinity (total dissolved solids) were established at three locations on the lower Colorado River: 1) Below Hoover Dam AZ-NV, 723 mg/l; 2) Below Parker Dam AZ-CA, 747 mg/l; 3) Imperial Dam AZ-CA, 879 mg/l. (CRBRWQCB, 1/18/2019)

The corresponding specific conductivity values are: 1) Below Hoover Dam AZ-NV,1314 µS/cml; 2) Below Parker Dam AZ-CA,1358 µS/cml; 3) Imperial Dam AZ-CA, 1598 µS/cm.

Colorado River (Below Imperial Dam) – Below Imperial Dam, the River's salinity will be controlled to meet the terms of the agreement with Mexico on salinity in Minute No. 242 of the International Boundary and Water Commission, entitled "Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River". This agreement states that measures will be taken to assure that the waters delivered to Mexico upstream from Morelos Dam will have annual average salinity concentration of no more than 115 ppm (+ 30 ppm) total dissolved solids greater than the annual average salinity
concentration of Colorado River water arriving at Imperial Dam. Title I of
Public Law 93-320 is the legislation which implements the provisions of Minute No. 242. Minute No. 242 and Title I constitute a federal numeric criterion and plan of implementation for the River below Imperial Dam. (CRBRWQCB, 1/18/2019)

The corresponding specific conductivity values are: no more than 209 µS/cm (+ 54 µS/cm) greater than the annual average conductivity of Colorado River water arriving at Imperial Dam.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Objective/Criterion Reference:

Water-Resources Investigations Report 86-4124

Objective/Criterion Reference:

Minute 242: Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River

Objective/Criterion Reference:

Water Quality Standards for Salinity Including Numeric Criteria and Plan of Implementation for Salinity Control Colorado River System.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 1975 and 2013.

Environmental Conditions:

QAPP Information:

USGS/Bureau of Reclamation Data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101825	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Sulfates
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of six sample(s) exceed the Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of six sample(s) exceed the Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. The sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101825, Sulfates	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126133

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance of 500 mg/l.

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	131269	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Total Dissolved Solids
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Line of Evidence (LOE} 125954 is replaced by LOE 231373 because LOE 231373 contains the flow-weighted data and threshold. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for conventional or other pollutants (Table 3.2 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 131269, Total Dissolved Solids	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

231373

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Quality Of Water Colorado River Basin Progress Report No. 25

Water Quality Standards for Salinity Including Numeric Criteria and Plan of Implementation for Salinity Control Colorado River System.

Data Associated with Quality Of Water Colorado River Basin Progress Report No. 25

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Colorado River Basin Region Water Quality Control Plan includes the following Salinity/TDS objectives for the Colorado River above and below Imperial Dam: Colorado River (Above Imperial Dam) - The Seven States Colorado River Salinity Control Forum developed water quality standards in 1975 for salinity. The flow-weighted average annual numeric criteria for salinity (total dissolved solids) were established at three locations on the lower Colorado River: 1) Below Hoover Dam AZ-NV, 723 mg/l; 2) Below Parker Dam AZ-CA, 747 mg/l; 3) Imperial Dam AZ-CA, 879 mg/l. (CRBRWQCB, 1/18/2019) Colorado River (Below Imperial Dam) – Below Imperial Dam, the River's salinity will be controlled to meet the terms of the agreement with Mexico on salinity in Minute No. 242 of the International Boundary and Water Commission, entitled "Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River". This agreement states that measures will be taken to assure that the waters delivered to Mexico upstream from Morelos Dam will have annual average salinity concentration of no more than 115 ppm (+ 30 ppm) total dissolved solids greater than the annual average salinity concentration of Colorado River water arriving at Imperial Dam. Title I of Public Law 93-320 is the legislation which implements the provisions of Minute No. 242. Minute No. 242 and Title I constitute a federal numeric criterion and plan of implementation for the River below Imperial Dam. (CRBRWQCB, 1/18/2019)

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Objective/Criterion Reference:

Minute 242: Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 1975 and 2013.

Environmental Conditions:

QAPP Information:

USGS/Bureau of Reclamation Data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101783	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess this pollutant. Zero of 162 samples exceed the Colorado River Basin Region Water Quality Control Plan water quality objective for each of the seven beneficial uses assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 162 samples exceed the Colorado River Basin Region Water Quality Control Plan water quality objective for each of the seven beneficial uses assessed. This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126748

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 8 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN-31, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126710

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126811

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126763

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126799

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126705

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Aquaculture

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101783, pH	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126789

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Agricultural Supply

Number of Samples:

162

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 0 of 162 samples exceeded the water quality standard for pH.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

The samples were collected between the dates of 2010-08-31 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101826	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Manganese
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2031
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Six of six samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Six of six samples exceed the California Secondary MCL for the "Municipal & Domestic Supply" beneficial use assessed. This exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101826, Manganese	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126102

Pollutant:

Manganese

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 6 of 6 samples exceeded the water quality standard for Manganese.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin). Aesthetic Qualities. All waters shall be free from substances attributable to wastewater of domestic or industrial origin or other discharges which adversely affect beneficial uses not limited to Producing objectionable color, odor, taste, or turbidity. (Water Quality Control Plan, Colorado River Basin Region).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's narrative objective for Aesthetic Qualities and Chemical Constituents. The Secondary MCL for manganese is 0.5 mg/L. (Cal. Code Regs., tit. 22, § 64449.)

Guideline Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	127649	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Turbidity
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2033
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The information indicates beneficial uses pertaining to this waterbody-pollutant combination may be threatened. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. 52 of the 102 samples exceed the California Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 52 of the 102 samples exceed the California Secondary Maximum Contaminant Level for the "Municipal & Domestic Supply" beneficial use assessed. This exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the following changes to the decision: The water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 127649, Turbidity	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

220747

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Tissue

Matrix:

Not Recorded

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP Sportfish Contamination in Lakes and Resrv data for Isabella Lake to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality standard for Endosulfan. Data were collected for 1 fish species (1 composite(s) of Channel Catfish each composed of 4 fish per composite).

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

This is a placeholder LOE use to generate a decision on the 2020 cyce. It should not be considered for assessment and should be deleted once it has been used for its purpose.

Objective/Criterion Reference:

Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Placeholder

Temporal Representation:

Placeholder

Environmental Conditions:

QAPP Information:

Placeholder

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 127649, Turbidity	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126033

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed NWIS data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 4 of 7 samples exceeded the water quality standard for Turbidity.

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's \Chemical Constituents\" objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment. "

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2014-08-27 and 2017-03-14

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 127649, Turbidity	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126726

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Colorado River (Imperial Reservoir to California-Mexico Border) to determine beneficial use support and results are as follows: 47 of 95 samples exceeded the water quality standard for Turbidity.

Data Reference:

Water quality data for federal, state, and tribal agencies submitted through the US EPA STorage and RETrival (STORET) database for the 2018 listing cycle.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

Guideline Reference:

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Spatial Representation:

The samples were collected at 7 monitoring site(s) (COCOPAH_INDIAN-BAR 12, COCOPAH_INDIAN-CDN 31, COCOPAH_INDIAN-CUE-35, COCOPAH_INDIAN-CUE 35, QUECHAN_WQX-CRD04, QUECHAN_WQX-CRR06, QUECHAN_WQX-CRU01)

Temporal Representation:

The samples were collected between the dates of 2010-12-02 and 2012-06-19

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	101822	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence are necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the two samples exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the two samples exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the two samples exceed the California Secondary MCL, for the "total" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the two samples exceed the California Secondary MCL, for the "dissolved" fraction, for the "Municipal & Domestic Supply" beneficial use assessed. Zero of the two samples exceed the California Toxics Rule criterion continuous concentrations to protect aquatic life in freshwater for the "Warm Freshwater Habitat" beneficial use assessed. The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 101822, Copper	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125991

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2016-08-22 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101822, Copper	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

126024

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The California Secondary MCL for copper is 1.0 mg/L (Title 22 California Code of Regulations).

Guideline Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2016-08-22 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 101822, Copper	Region 7
Colorado River (Imperial Reservoir to California-Mexico Border)

LOE ID:

125992

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the USGS National Water Information System.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)

Evaluation Guideline:

The California Secondary MCL for copper is 1.0 mg/L (Title 22 California Code of Regulations).

Guideline Reference:

Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations

Spatial Representation:

The samples were collected at 1 monitoring site(s) (USGS-09521100)

Temporal Representation:

The samples were collected between the dates of 2016-08-22 and 2016-12-20

Environmental Conditions:

QAPP Information:

QAPP not required for federal data

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.